<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>圣杯布局</title>
    <style>
        *{
            margin:0;
            padding:0;
        }
        .container{
            display: flex;
            flex-direction: column;
            height: 100vh;
        }
        header{
            background: #ffff00;
        }
        footer{
            background: #ffff00;
        }
        section{
            flex: 1;
            background: #ff0000;
            display: flex;
        }
        .left{
            background: #cccccc;
            flex-basis: 200px;
            /* //相当于宽 */
        }
        .right{
            background: #cccccc;
            flex-basis: 200px;
        }
         .content{
             flex: 1;
             background: orange;
         }
    </style>
</head>
<body>
    <div class="container">
        <header>头部</header>
        <section>
            <div class="left">左</div>
            <div class="content">中</div>
            <div class="right">右</div>
        </section>
        <footer>底部</footer>
    </div>
</body>
</html>